I2C bus init error when specifying frequency on M0

[deshipu]

On Feather M0, when I try to specify the clock frequency for the I2C bus, I get an OSError:

>>> i2c = I2C(SCL, SDA, frequency=10000)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
OSError: I2C bus init error

In addition, after the creation of that I2C object failed, any subsequent attempts at creating it result in a "Pin in use" errror:

>>> i2c = I2C(SCL, SDA)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
ValueError: Pin PA23 in use

[deshipu]

That means that I can't test the BNO055 sensor on the Feather M0.

[tannewt]

Ok, sorry about this. It'll be a couple more days until I can fix it.

[tannewt]

Why are you trying to run the bus at 10kHz? The datasheet says it can run up to 400kHz. 100kHz should work fine too.

[deshipu]

Yeah, those are too fast for this sensor, at least with the default clock stretching timeout.

[tannewt]

Ah, ok. It sounds like this really is that we need to lengthen the clock stretch timeout for nativeio.I2C. Can we consolidate this with #91? 10kHz seems non-standard enough that its ok not to support it.

[deshipu]

If that value is invalid, it should raise a ValueError and exit cleanly, cleaning up all the pins afterwards.

[tannewt]

Ah true. Will do that.

[deryakitis]

Hi, when I try to run the circuitpython code below for an i2c of vcnl sensor and crickit robot on feather m0 express it gives me an ''SCL in use" error. Do you have an idea about how can I fix that?

import time
import adafruit_vcnl4010
import board
import busio
from adafruit_crickit import crickit

i2c = busio.I2C(board.SCL, board.SDA)
while not i2c.try_lock():
pass
print("I2C addresses found:", [hex(device_address)
for device_address in i2c.scan()])
i2c.unlock()
sensor = adafruit_vcnl4010.VCNL4010(i2c)
motor_1 = crickit.dc_motor_1
motor_2 = crickit.dc_motor_2
while True:
motor_1.throttle = 1 # full speed forward
motor_2.throttle = -1 # full speed backward
time.sleep(1)

motor_1.throttle = 0.5  # half speed forward
motor_2.throttle = -0.5 # half speed backward
time.sleep(1)

motor_1.throttle = 0  # stopped
motor_2.throttle = 0  # also stopped

time.sleep(1)

motor_1.throttle = -0.5  # half speed backward
motor_2.throttle = 0.5   # half speed forward
time.sleep(1)

motor_1.throttle = -1  # full speed backward
motor_2.throttle = 1   # full speed forward
time.sleep(1)

motor_1.throttle = 0  # stopped
motor_2.throttle = 0  # also stopped
time.sleep(0.5)

proximity = sensor.proximity  # Proximity has no units and is a 16-bit
                              # value.  The LOWER the value the further
                              # an object from the sensor (up to ~200mm).
print('Proximity: {0}'.format(proximity))
ambient_lux = sensor.ambient_lux
print('Ambient light: {0} lux'.format(ambient_lux))
time.sleep(1.0)

and the error is:
code.py output:
Traceback (most recent call last):
File "code.py", line 8, in
ValueError: SCL in use

line 8 is:
i2c = busio.I2C(board.SCL, board.SDA)

[caternuson]

When you import the crickit library, it sets up the I2C bus:
https://github.com/adafruit/Adafruit_CircuitPython_Crickit/blob/master/adafruit_crickit.py#L382
So when you try to do it again with:

 i2c = busio.I2C(board.SCL, board.SDA)

It hits that error since the pins, both SCL and SDA, are in use. It only mentions SCL since that's the first one it tries to use.

Also, you don't need to worry about doing the lock and the scan. So change all this:

i2c = busio.I2C(board.SCL, board.SDA)
while not i2c.try_lock():
pass
print("I2C addresses found:", [hex(device_address)
for device_address in i2c.scan()])
i2c.unlock()
sensor = adafruit_vcnl4010.VCNL4010(i2c)

to just this:

sensor = adafruit_vcnl4010.VCNL4010(board.I2C())

[deryakitis]

Firstly, thaks for the quick response! I inverted the code into the way you said, now I am getting the same error but for SDA. Error: Traceback (most recent call last): File "code.py", line 7, in <module> ValueError: SDA in use Code: import time import adafruit_vcnl4010 import board import busio from adafruit_crickit import crickit sensor = adafruit_vcnl4010.VCNL4010(board.I2C()) #i2c = busio.I2C(board.SCL, board.SDA) #while not i2c.try_lock(): # pass #i2c.unlock() #sensor = adafruit_vcnl4010.VCNL4010(i2c) Carter Nelson <notifications@github.com>, 7 Ağu 2019 Çar, 12:15 tarihinde şunu yazdı:

…

When you import the crickit library, it sets up the I2C bus: https://github.com/adafruit/Adafruit_CircuitPython_Crickit/blob/master/adafruit_crickit.py#L382 So when you try to do it again with: i2c = busio.I2C(board.SCL, board.SDA) It hits that error since the pins, both SCL and SDA, are in use. It only mentions SCL since that's the first one it tries to use. Also, you don't need to worry about doing the lock and the scan. So change all this: i2c = busio.I2C(board.SCL, board.SDA)while not i2c.try_lock():passprint("I2C addresses found:", [hex(device_address)for device_address in i2c.scan()]) i2c.unlock() sensor = adafruit_vcnl4010.VCNL4010(i2c) to just this: sensor = adafruit_vcnl4010.VCNL4010(board.I2C()) — You are receiving this because you commented. Reply to this email directly, view it on GitHub <#95?email_source=notifications&email_token=AMUSIOWWWBLV6ZLIKGSIQULQDL7J3A5CNFSM4C7YWAT2YY3PNVWWK3TUL52HS4DFVREXG43VMVBW63LNMVXHJKTDN5WW2ZLOORPWSZGOD3ZDFXA#issuecomment-519189212>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AMUSIORIR4JH6BLJY4AE6OTQDL7J3ANCNFSM4C7YWATQ> .

[dhalbert]

There's an underlying problem that the Crickit library doesn't use board.I2C(). It creates its own I2C object:

https://github.com/adafruit/Adafruit_CircuitPython_Crickit/blob/617bb0787f2c61283d248632a62b27be80f64b29/adafruit_crickit.py#L382

That should be fixed. In the meantime you can do this:

i2c = crickit.seesaw.i2c_device.i2c

and then use that i2c object for the VCNL.

[caternuson]

oh, yah. good catch. thanks @dhalbert

@deryakitis here you go:

Adafruit CircuitPython 4.0.2 on 2019-06-27; Adafruit Feather M4 Express with samd51j19
>>> import time
>>> import adafruit_vcnl4010
>>> import board
>>> import busio
>>> from adafruit_crickit import crickit
>>> sensor = adafruit_vcnl4010.VCNL4010(crickit.seesaw.i2c_device.i2c)
>>> sensor.ambient_lux
296.0
>>>